User:R. Eric Collins/MBL/Felsenstein

Phylogeny & Morphometrics

• genetic covariance
• selective covariance
  • the same environmental conditions select changes in two or more traits -- even though they may have no genetic covariance
  • arctic: fur coloration, size, limb length; bergman, allen rules
  • all change at same time because environment has changed
  • not that they necessarily have genetic covariance
• superpositions can be misleading, multiple superpositions correspond to the same change
• in 1/0 stochastic model, you are just as likely to 'come back' right after switch as much later
  • 'coming back', biologically, seems less likely after long time e.g. the brownian model

• running the covariance estimator longer only estimates the noise better
• covariance? 100 numerical values --> 100 presence/absence --> <100 on a tree
  • lose power to measure covariance at each step

• with genomes, will be able to get QTL within species, see them change across species
• resign yourself to uncertainty

• no "post-modern synthesis"

History Lesson

in 1957 the average university got a computer it was as powerful as a singing birthday card today (really?)

• first numerical phylogeny, of bees, by Sokal and Michener 1957
  • Michener wanted to make phenetic inference into a phylogeny
• "the most parsimonious thing evolution could do would be to not change anything"